The tower, sheathed in copper-coloured glass, actually became Europe's tallest in September, while still under construction, when it exceeded London's 310-metre (1,017ft) Shard, according to the construction information company Emporis.

Mercury City's reign is likely to be almost as short. Its next-door to the under-construction Federation Tower, which is to reach 506 metres (1,660ft) when it's completed next year.

Both are in a sprawling development called Moscow City that also holds two other buildings that once were Europe's tallest.

The complex is an eye-catching demonstration of Moscow's transformation from drab shabbiness to swaggering prosperity, driven largely by oil and natural gas revenues.

But competing with European countries for tallest building is playing in the minor leagues. There are nearly 60 buildings in North America, Asia and the Middle East that are taller, topped by Dubai's Burj Khalifa - about 2.5 times taller than Mercury city at 828 metres (2,717ft).